Apparatus and method for human powered movement of a scaffold structure

ABSTRACT

A human powered movement apparatus for moving a wheeled structure or scaffold. The human powered movement apparatus having a horizontal lever bar operable by a person working on a platform of the scaffold. The horizontal lever bar is connected, by way of a shaft, to a wheel frame with a set of unidirectional wheels. When the operator moves the horizontal lever bar in one direction, the wheel frame pivots about one of the unidirectional wheels while the other unidirectional wheel rolls freely causing the scaffold to advance in an arc. Movement of the horizontal lever bar in the opposite direction results in a similar movement with the behavior of the unidirectional wheels reversed. Repeated movement of the horizontal lever bar results in forward movement of the scaffold through a cambering motion.

FIELD OF THE INVENTION

This invention relates generally to scaffold structures, and, more particularly, to a method and apparatus for human powered movement of a scaffold structure.

BACKGROUND OF THE INVENTION

Scaffold structures are used extensively in the construction industry and in building renovations and repairs. In order to move a scaffold structure from one place to another, it is typically necessary to climb off the scaffold, move it, and then climb on again. This process can be very time consuming. As such, various systems have been proposed that allow movement of the scaffold without dismounting.

Typically, systems for moving scaffolding without dismounting have focused on motorized rather than manual solutions. One simpler motorized system proposed for moving scaffolding involves the use of a power drill connected to a shaft running from the top of the scaffold to a wheel assembly in contact with the ground. The shaft engages with a gear, which then engages with a drive axle for the wheels. Operation of the drill is intended to propel the scaffold in a forward or reverse direction. This system has the drawback that it is limited by the torque of the drill, the need for a power source, and the expense of the drill, and the like.

Although it is believed that human powered systems have not been used with scaffold structures, there are many known human powered systems in other areas. A basic example is a bicycle-like apparatus in which a gear is turned by feet and the gear is connected by a pulley or chain to another gear, which transmits the movement of the feet to a wheel or wheels. Another known system, which has been used in children's toys, uses a twisting motion of a shaft connected to a wheel frame to generate forward motion by movement of wheels on each end of the wheel frame alternately through an arc of a circle pivoting around the opposite wheel. This twisting system seems to be restricted to children's toys, perhaps due to a perceived limited range of motion, difficulty in operation, or the like.

As briefly noted above, conventional motorized or human powered movement mechanisms have various drawbacks. Motorized mechanisms are generally more expensive than manual systems and they may also need additional maintenance or result in additional time/expense if there is any kind of a failure of the motor or motor mechanisms. In addition, the dependence of motorized systems on electricity or fuel sources adds further difficulty in remote areas and adds to costs.

With regard to conventional human powered mechanisms, there can be issues with regard to the cost of the parts required and/or issues with mechanical breakdown of the parts. These problems are generally due to the complexity of conventional human powered mechanisms. Simpler human powered systems are often viewed as having too limited a range of movement or to be difficult to operate.

With the growing need for construction equipment and construction capabilities in developing nations and with the growth of the do-it-yourself home repair market, there is a need for a cost effective, efficient system of human powered movement of scaffold structures and other similar structures, which eliminates the need to dismount in order to move the structure.

SUMMARY OF THE INVENTION

Embodiments of the invention are generally directed to an apparatus for human powered movement that makes use of a twisting force applied to a center point of two unidirectional wheels spaced at a distance. When applied in one direction, the twisting force causes one of the wheels to move forward in an arc while the second wheel remains stationary (since it cannot move in a reverse direction). The twisting force is then applied in the other direction to cause the second wheel to move forward in an arc while the first wheel remains stationary. Thus, the apparatus moves a structure attached thereto in a generally forward direction.

In one broad aspect of the invention, there is provided an apparatus for human-powered movement of a scaffold structure. The apparatus includes: an operating device, a wheel frame, and a transmission system. The transmission system is connected between the operating device and the wheel frame and is connectable to the scaffold structure. Also, the transmission system is connected such that actuation of the operating device causes a corresponding movement in the wheel frame. The movement apparatus also includes two unidirectional wheel assemblies provided at opposite ends of the wheel frame. Each unidirectional wheel assembly includes a wheel bracket connected to the wheel frame, and a unidirectional wheel supported in the wheel bracket.

The apparatus provides simple, inexpensive construction that, when attached to and supporting a scaffold structure, allows movement of the scaffold structure by simply twisting the operating device. Since there are few parts, maintenance of the apparatus is relatively simple. In a preferred case, the scaffold structure to which the apparatus is connected has a set of wheels supporting the end opposite the apparatus.

In a further aspect of the present invention, the unidirectional wheel includes: a bi-directional main wheel, and a sub-wheel arranged in the wheel bracket adjacent to the bi-directional main wheel and adjacent to the wheel bracket. The unidirectional wheel functioning such that movement of the bi-directional main wheel in a first direction causes the sub-wheel to come into contact with the wheel bracket and prevents further rotation of the bi-directional main wheel in the first direction. Alternatively, movement of the bi-directional main wheel in a second direction causes the sub-wheel to move out of contact with the wheel bracket allowing further movement of the bi-directional main wheel in the second direction.

In another aspect of the present invention, the unidirectional wheel as described above includes: a bi-directional main wheel, and a block connected to the wheel bracket and arranged adjacent to the bi-directional main wheel. The unidirectional wheel functioning such that movement of the bi-directional main wheel in a first direction causes the block to abut against the bi-directional main wheel and the wheel bracket preventing further rotation of the bi-directional main wheel in the first direction. Alternatively, movement of the bi-directional main wheel in a second direction causes the block to disengage from the bi-directional main wheel or the wheel bracket allowing further movement of the bi-directional main wheel in the second direction.

In the aspects described above, the apparatus may include a support mechanism connectable to the scaffold structure or provided as a part thereof. The support mechanism designed such that activating the support mechanism causes the scaffold structure to be unsupported by the unidirectional wheel assemblies. Conversely, deactivating the support mechanism causes the scaffold structure to be at least partially supported by the unidirectional wheel assemblies.

The support mechanism as described above may include: a support bar, a biasing device connected to the scaffold structure for biasing the support bar to a first position, and a latching mechanism connected to the support bar wherein the latching mechanism may be latched to the scaffold structure for retaining the support bar in a second position counter to the first position.

In the aspects described above, the transmission system may include: a substantially inclined main shaft, a substantially vertical lower shaft connected between the wheel frame and the main shaft, and an upper shaft connected between the main shaft and the operating device.

In another aspect of the present invention there is provided an apparatus for human-powered movement of a scaffold structure. The apparatus including: a horizontal lever bar, a horizontal wheel frame, and a shaft. The shaft being connected between the center of the lever bar and the center of the wheel frame and connectable to the scaffold structure such that the scaffold structure is supported by the apparatus. Also, the shaft being connected such that actuation of the lever bar causes a corresponding movement in the wheel frame. The apparatus also including two unidirectional wheel assemblies provided at opposite ends of the wheel frame. Each unidirectional wheel assembly includes a wheel bracket connected to the wheel frame, and a unidirectional wheel supported in the wheel bracket. The apparatus designed such that actuating the lever bar in a first direction causes the wheel frame to pivot in a first angular direction about a first unidirectional wheel assembly attached to a first end of the wheel frame, and actuating the lever bar in a second direction causes the wheel frame to pivot in a second angular direction about a second unidirectional wheel assembly attached to a second end of the wheel frame opposite to the first end, resulting in movement of the scaffold structure.

In another aspect of the present invention there is provided a method for human powered movement of a scaffold structure. The method including providing a movement apparatus to the scaffold structure. The movement apparatus including: an operating device, a wheel frame, and a transmission system. The transmission system being connected between the operating device and the wheel frame and connectable to the scaffold structure. Also, the transmission system being connected such that actuation of the operating device causes a corresponding movement in the wheel frame. The apparatus also including two unidirectional wheel assemblies provided at opposite ends of the wheel frame. Each unidirectional wheel assembly includes a wheel bracket connected to the wheel frame, and a unidirectional wheel supported in the wheel bracket. The method further includes actuating the operating device in a first direction causing the wheel frame to pivot in a first angular direction about a first unidirectional wheel assembly attached to a first end of the wheel frame. Next, the method includes actuating the operating device in a second direction causing the wheel frame to pivot in a second angular direction about a second unidirectional wheel assembly attached to a second end of the wheel frame opposite to the first end. The method provided such that pivoting the wheel frame in the first angular direction and then pivoting the wheel frame in the second angular direction results in movement of the scaffold structure.

In the method described above, an operator may actuate the operating device using the operator's arms and hands.

In an alternative to the method described above, an operator may actuate the operating device using the operator's legs and feet.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of embodiments of the invention, and to show more clearly how they may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:

FIG. 1 is a side view of a scaffold according to an embodiment of the invention;

FIG. 2 is a front view of the scaffold of FIG. 1;

FIG. 3 is a rear view of the scaffold of FIG. 1;

FIG. 4 is a front view of the support mechanism for the scaffold of FIG. 1;

FIG. 5 is a cross-sectional view of the support mechanism and latch mechanism of FIG. 4;

FIG. 6 is a front view of the movement apparatus for the scaffold of FIG. 1;

FIG. 7 shows a side view of a unidirectional wheel for the scaffold of FIG. 1;

FIG. 8 shows a cross-sectional view of a unidirectional wheel along the plane shown in FIG. 6;

FIG. 9 is a schematic showing motion of the front wheels of the scaffold of FIG. 1 during operation of the movement system;

FIG. 10 shows a side view of an alternate arrangement for the unidirectional wheel;

FIG. 11 shows a front view of an alternate arrangement for the unidirectional wheel;

FIG. 12 shows a front view of an alternate support mechanism;

FIG. 13 shows a side view of an alternative embodiment of the movement apparatus having an inclined main shaft;

FIG. 14 shows a side view of an alternative embodiment of the operating device wherein actuation thereof is in the vertical plane;

FIG. 15 shows a front view of an alternative embodiment of the operating device wherein actuation thereof is in the vertical plane; and

FIG. 16 is a front view of a scaffold having the shaft of the movement apparatus journalled to the scaffold.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Referring to FIG. 1 to FIG. 3 a wheeled structure 10 according to our embodiment of the invention is shown. The wheeled structure 10 includes a scaffold structure 12 and a movement apparatus 14. While this embodiment relates to a scaffold structure 12, embodiments of the invention may include other similar structures.

The scaffold 12 is generally a cubical framed structure of oblong dimensions having vertical support members 20, generally situated at the corners of scaffold 12. Vertical support members 20 are interconnected by a plurality of horizontal support members 22 to define the cubical oblong structure. Horizontal support members 22 are securely fastened to vertical support members 20 by bolted joints, weldments or other suitable means. In the preferred embodiment horizontal support members 22 are removably connected to vertical support members 20. In particular, the ends of horizontal support members 22 have transverse protrusions 24 that are received in pockets 26 affixed to vertical supports 20 as indicated by the insertion arrow and attachment lines shown in FIG. 1. This allows a modular scaffold 12 that can be re-configured and re-assembled as necessary. Various lengths and sizes of vertical support members 20 and horizontal support members 22 can be provided to allow different scaffold dimensions. In addition, reinforcing members 36 may be provided to solidify scaffold 12 by interconnecting vertical support members 20 or horizontal support members 22 depending on the anticipated loading of scaffold 12. Reinforcing members 36 may be orientated in any direction, although in FIG. 1, they are shown to be vertical. To further facilitate modularity, reinforcing members 36 can also be removable.

A platform unit 30 is provided in proximity to the top of scaffold 12. Platform unit 30 generally comprises a platform frame 32 and a platform 34. Platform frame 32 is supported on reinforcing members 36 at the front and rear portions of scaffold 12 by demountable connections, such as overhanging hooks 37. In alternative embodiments platform frame 32 can be supported by vertical supports 20 or horizontal supports 22. Platform 34 is suspended atop platform frame 32 and is of similar size to the dimensions of scaffold 12 in plan view.

At the rear of scaffold 12 is a ladder structure 38 for climbing up scaffold 12 to platform 34. Ladder structure 38 is composed of several horizontal steps 40 solidly interconnected to a rearward vertical support 20 and a central rear vertical support 42. Alternatively, a ladder can be latched to scaffold 12 by a demountable connection device such as hooks (not shown).

The structural components of scaffold 12 are generally made of steel and preferably have hollow square cross-sections to reduce weight and provide conduits for elements of movement apparatus 14. Nonetheless, it is possible to use other materials and cross-sections that provide sufficient strength for applications using a scaffold.

As shown in FIG. 3, the rear section of the scaffold 12 is provided with a pair of rear wheels 44 at the base of each of the rear vertical support members 20. Preferably, rear wheels 44 are provided with a mating attachment 46 that fits within the hollow portions of rear vertical support members 20 such that rear wheels 44 are removable from the rear vertical support members 20. In this embodiment, rear wheels 44 may be castor-type wheels. The size of the rear wheels 44 may be varied depending on the size and weight of scaffold 12.

In a preferred embodiment, movement apparatus 14 is located proximal to the front of scaffold 12. Referring to FIG. 6, movement apparatus 14 comprises a shaft 50, a wheel frame 52, two unidirectional wheel assemblies 54 and an operating device 56. Shaft 50 is generally cylindrical and is received inside a hollow vertical support 60 of scaffold 12 (see FIG. 2). Shaft 50 has a top portion 50 a and a bottom portion 50 b that spans from operating device 56 to wheel frame 52. Shaft 50 may be journalled to scaffold 12 by a series of bearings 62 (see FIG. 16), or other suitable method, to reduce radial deflections of shaft 50 during operation and to provide a supporting device for connecting scaffold 12 to movement apparatus 14. A supporting device such as bearing 62 in FIG. 2, allows movement apparatus 14 to bear some of the weight of scaffold 12, enabling movement apparatus 14 to produce substantial movement of scaffold 12 when movement apparatus 14 is actuated. A supporting device can be any device allowing movement apparatus of carrying a load such as a plate, collar, bearing or other similar device.

Operating device 56 is rigidly connected to the top portion 50 a for rotation of the shaft 50 upon twisting the operating device 56. Wheel frame 52 is rigidly connected to the bottom portion 50 b such that twisting operating device 56 causes rotation of wheel frame 52 through shaft 50. The rigid connections at 50 a and 50 b can be weldments, bolted joints, clamps or other suitable attachment means. The connection at 50 b should be made such that shaft 50 passes through vertical axis 68 (see FIG. 2), which extends vertically substantially from the center of wheel frame 52.

Referring to FIG. 4, operating device 56 is preferably a horizontal lever bar 58 provided with rubber grips 59 at the ends thereof to assist with manual movement of operating device 56 by an operator's hands. In an alternative embodiment (not shown), operating device may be a steering wheel to provide twisting of the operating device 56 at a multitude of angles. In a further embodiment, operating device 56 may be designed and positioned such that it is operated by an operator's feet and foot straps (not shown) may be provided to keep the feet on the operating device 56 during movement. In this way, an operator can make use of the larger muscles in the legs to apply additional force to the operating device 56.

Wheel frame 52 is horizontally disposed within the limits of vertical supports 20 and having appreciable clearance 70 for complete 360° rotation of wheel frame 52 about vertical axis 68.

Each unidirectional wheel assembly 54 is connected to wheel frame 52 via a U-shaped wheel bracket 72 at opposing ends of wheel frame 52. Wheel bracket 72 is fastened to wheel frame 52 by weldments or other suitable means such that two lateral sides 76 extend downward from wheel frame 52.

Referring to FIG. 7 and FIG. 8, on each of the lateral sides 76 of wheel bracket 72, there are co-axial bores 78 for insertion and attachment of a wheel axle 80. A wheel 55 is coupled to wheel axle 80 amid lateral sides 78 co-axial bores 78 are located downward from wheel frame 52 such that wheel 55 has ample clearance to spin in wheel bracket 72. Wheel axle 80 is generally cylindrical and smooth to permit smooth spinning of wheel 55. The opposing ends of wheel axle 80 have portions that extend beyond lateral sides 76. The extended portions have threading for attachment of wheel nuts 82 to prevent axial movement of wheel axle 80 between lateral sides 76. Wheel nuts 82 are tightly fastened to the exterior face of lateral sides 76 to prevent spinning of wheel axle 80 in co-axial bores 78. Other methods of securing wheel axle 80 in place are possible, such as cotter pins, bushings or the like. In such alternative embodiments, wheel axle 80 may freely spin in co-axial bores 78. Coincidentally, wheel 55 may be securely attached to wheel axle 80 such that wheel 55 spins with wheel axle 80.

Unidirectional wheel assembly 54 comprises a bi-directional main wheel 90, a brake pad 100, and a spring 102. A bi-directional wheel is one that can rotate freely in both clockwise and counter-clockwise directions. Main wheel 90 is rotatably coupled to wheel axle 80 and has bushings 92 that appreciably prevent axial movement of the wheel 90. Bushings 92 are disposed on opposing sides of main wheel 90 and between lateral sides 76.

Brake pad 100 is generally a flat rectangular block having a narrowed head portion 104 and a beveled end 106. Head portion 100 extends from a neck 108 beginning at the top of brake pad 100. Head portion 104 has a tapered portion 105 so as to be fitted through an aperture 110 in wheel bracket 72. A flange 112 is featured on the bottom of head portion 104 to connect brake pad 100 to wheel bracket 72 and substantially prevent detachment thereof. Aperture 110 is situated forward from the spinning axis of main wheel 90 and above main wheel 90 such that when brake pad 100 is substantially vertical, beveled portion 106 is in contact with the upper-front surface of main wheel 90 and there is a clearance 120 between brake pad 100 and the bottom of wheel bracket 72. Beveled portion 106 is generally slightly wider than main wheel 90 so as to provide maximum stopping power. The angle of the bevel is such that it generally follows the slope of the main wheel 90 at the point where they touch in the vertical position.

Spring 102 has two opposing ends with hooks 116 formed thereon. One hook 116 is mounted to a first hoop 114, which is rigidly attached to brake pad 100 roughly midway between the head portion 104 and the beveled portion 106. The other hook 116 is mounted to a second hoop 118, which is rigidly attached to the bottom of wheel bracket 72. Second hoop 118 is situated rearward of aperture 110 such that spring 102 is stretched slightly beyond its relaxed state when brake pad 100 is substantially vertical as previously described.

In operation, unidirectional wheel assembly 54 functions as described below. When main wheel 90 is rotated in the clockwise direction, brake pad 100 and beveled portion 106 are biased at a forward angle from their vertical position. Clearance 120 is maintained, allowing main wheel 90 to spin under minimal friction caused by spring 102 pulling beveled portion 106 into main wheel 90. Thus, forward motion is permitted. Alternatively, when main wheel 90 is rotated counter-clockwise, brake pad 100 and beveled portion 106 are pulled upward and inward to main wheel 90 by spring 102 and friction between beveled portion 106 and main wheel 90. Clearance 120 is withdrawn and brake pad 100 frictionally contacts main wheel 90 and the bottom of wheel bracket 72 such that it is jammed. Consequently, main wheel 90 cannot rotate in the counter-clockwise direction and no rearward motion of main wheel 90 is permitted. When main wheel 90 is rotated clockwise again, brake pad 100 disengages with the bottom of wheel bracket 72 allowing forward motion as described above.

In a preferred embodiment, wheeled structure 10 can also be provided with a support mechanism 130 (as shown in FIG. 4) that allows wheeled structure 10 to be locked in place when it is desired to disengage movement apparatus 14 from the ground either by lifting movement apparatus 14 off the ground (as possible in FIG. 16) or by removing the load of scaffold 12 supported by movement apparatus 14 (as possible in FIG. 4). Support mechanism 130 comprises support bars 132 that extend from the upper part of scaffold 12 to the lower part of scaffold 12. The support bars 132 each have feet 134 at the base thereof and are attached together by a support connection bar 136 at the top thereof. Preferably, support bars 132 run through hollow portions of vertical support members 20 at the front-end section of scaffold 12. A biasing spring 142 is provided between support connection bar 136 and the upper front horizontal support member 22 such that when support mechanism 130 is inactivated, feet 134 are held substantially off the ground by biasing spring 142 to permit rolling of wheeled structure 10. A locking mechanism 140 may be provided in combination with support connection bar 136 to lock feet 134 in an active state. Locking mechanism 140 comprises a lever arm 146 pivotally connected to horizontal support member 22 through a lever bracket 145 such that lever arm 146 can be used by an operator to apply downward pressure on support connection bar 136 to force feet 134 downward and into contact with the ground to raise the scaffold 12. A latching mechanism 148 comprising a hinged latch 150 and latch spring 152 is also provided for holding lever arm 146 when it is actuated in the downward position. The spring loaded latching mechanism 148 shown in FIG. 5 is one possibility for securing lever arm 146. Other latching mechanisms known in the art may be implemented without deviating from the scope of the present invention.

Functionally, pressing downward on lever arm 146 causes support connection bar 136 to compress biasing spring 142. In addition, support bars 132 are pushed downward through vertical support members 20. Thus, feet 134 forcefully extend from the vertical support members 20 to make contact with the ground and raise the front section of scaffold 12 such that movement apparatus 14 no longer supports scaffold 12. In FIG. 4, movement apparatus 14 would still be in contact with the ground, as shaft 50 would slide downward relative to scaffold 12 and supporting device 62 would no longer support scaffold 12 as in its previous abutting fashion with horizontal support member 22 as shown in FIG. 2. Conversely, in FIG. 16 the movement apparatus 14 would be lifted off the ground entirely since shaft 50 is connected to scaffold 12 at a series of bearings 62 which prevent shaft 50 from sliding up or down relative to scaffold 12. When the load of scaffold 12 is completely removed from movement apparatus 14 and feet 134 are in their active state, lever arm 146 can be latched in place by latching mechanism 148. In practice, the latching mechanism 148 operates such that when lever arm 146 contacts hinged latch 150 in a downward motion, hinged latch 150 pivots inward, compressing latch spring 152. When lever arm 146 proceeds past hinged latch 150, latch spring 152 decompresses, biasing hinged latch 150 outward and preventing lever arm 146 from returning to an upward position. In this way, wheeled structure 10 can be locked in place until it next needs to be moved. In order to move wheeled structure 10, locking mechanism 140 is released by de-latching lever arm 146 from the latching mechanism 148 by manually pressing hinged latch 150 inward. The compressive forces in biasing spring 142 exert an expansive force causing support connection bar 136 to travel upwardly, also raising lever arm 146. The upward movement of support connection bar 136 pulls support bars 132 upward, lifting feet 134 off the ground until movement apparatus 14 partially supports scaffold 12 and feet 134 are no longer in contact with the ground. In this state, biasing springs 142 only support the weight of the support mechanism 130 and its sub-components attached thereto. The support mechanism above is described only for illustration purposes, as it is conceivable that no support mechanism be implemented or that alternative support mechanisms be implemented.

Referring now to. FIG. 9, in operation, when a user wants to move wheeled structure 10, locking mechanism 140 is first disengaged, allowing the movement apparatus 14 to support scaffold 12. The user then twists operating device 56 in one direction, which causes shaft 50 to twist in the same direction, causing wheel frame 52 to turn in the same direction and allowing one of the unidirectional wheel assemblies 54 to spin forward. In the present embodiment, unidirectional wheels 55 are orientated to spin in the forward direction as shown by the arrow in FIG. 9. If operating device 56 is twisted such that shaft 50 twists in the counter-clockwise direction, the left unidirectional wheel assembly 54L will be held stationary as it would tend to spin rearward due to the wheel frame 52 wanting to pivot about vertical axis 68. Since, left unidirectional wheel assembly 54L moves in only one direction, wheel frame 52 pivots substantially about left unidirectional wheel assembly 54L. Consequently, right unidirectional wheel assembly 54R spins forward, pivoting about left unidirectional wheel assembly 54L, so that right unidirectional wheel assembly 54R arrives at point P1 following an arc of radius R and advancing wheeled structure 10 a forward distance related to amount of twist in operating device 56. Generally, point P1 is at an arc distance less than 90° to provide appreciable forward movement, however, different maneuvers such as turning will require alternative arc lengths. Next, if operating device 56 is twisted such that shaft 50 twists in the clockwise direction, the right unidirectional wheel assembly 54R will be held stationary at point P1 as it would tend to spin rearward due to the wheel frame 52 wanting to pivot about vertical axis 68. Since, right unidirectional wheel assembly 54R is locked, wheel frame 52 pivots substantially about P1. Consequently, left unidirectional wheel assembly 54L spins forward, pivoting about P1, so that left unidirectional wheel assembly 54L arrives at point P2, again following an arc of radius R and advancing wheeled structure 10 a forward distance related to amount of twist in operating device 56. Twisting operating device 56 counter-clockwise once more would bring right unidirectional wheel assembly 54R to point P3. It can be appreciated that repeating these motions continuously results in forward motion of wheeled structure 10.

Interestingly, wheeled structure 10 can also be moved in the reverse direction by first completing a 180° turn of the operating device 56 and then twisting operation device 56 back and forth in a similar manner but with unidirectional wheel assemblies 54 now driving in the opposite direction. Alternatively, when the support mechanism 130 is engaged to raise unidirectional wheel assembly 54 off of the ground, operating device 56 may be positioned with unidirectional wheel assembly 54 either facing forward or facing rearward depending on the desired direction of travel. The support mechanism 130 can then be disengaged lowering the unidirectional wheel assembly 54 to the ground and the operating device 56 may be twisted to move in the desired direction. It is preferred that an indicator be featured on operating device 56 to specify the direction of travel to the operator.

Although a scaffold 12 has been described, it will be understood to one of skill in the art that the movement apparatus 14 for moving the scaffold 12 can be applied to various other wheeled structures 10 or structures that could have wheels applied to them, such as It will further be understood by one of skill in the art that there may be other embodiments or implementations in which the rear wheels 44 may not be necessary. For example, if the weight of the structure to which the movement apparatus 14 is provided is such that a rear section may be dragged by the operation of the movement apparatus 14.

It will also be understood by one of skill in the art that the size and dimensions of the scaffolding 12 may be varied according to particular needs. In order to accommodate a variety of needs, scaffold 12 and movement apparatus 14 may be provided in modular sections that can be connected to allow for taller or wider scaffolds 12.

It will be further understood to one of skill in the art that there may be various mechanisms for constructing the unidirectional wheel assemblies 54 in order to provide for motion in only one direction by the wheels. In this particular embodiment the use of a brake pad 100 has been used because of its relative simplicity of construction and operation and thus lower cost.

In additional embodiments, other types of unidirectional wheel assemblies are possible such as alternative unidirectional wheel assembly 200 depicted in FIG. 10 and FIG. 11. In this embodiment, the wheeled structure 10 as described remains essentially unchanged and as such, corresponding reference numerals will be used in conjunction with the following description. Alternative unidirectional wheel assembly 200 comprises a bi-directional main wheel 90 as previously described and a bi-directional sub-wheel 202 attached to lateral sides 76 of wheel bracket 72. Sub-wheel 202 is rotatably coupled to a secondary axle 204. The secondary axle 204 is located in slots 206 of wheel bracket 72, which permits a rolling-sliding joint for secondary axle 204 to be received within lateral sides 76. It is noted that lateral sides 76 must be of a shape that accommodates attachment of both wheel axle 80 and secondary axle 204. Secondary axle 204 has opposing ends that extend beyond lateral sides 76. These ends are typically threaded so that sub-wheel nuts 208 can be fastened to secondary axle 204 to prevent axial movement between lateral sides 76. Other fasters can be implemented as suggested previously. To further prevent axial movement of sub-wheel 202, bushings 210 are provided on opposing sides of sub-wheel 202 and between lateral sides 76.

Each slot 206 is located substantially above and forward of wheel axle 80. Slot 206 is oblong and extends diagonally downward and forward from an upper aperture 212 to a lower aperture 214. Sub-wheel 202 is sized such that its radius is larger than the perpendicular distance between the center of upper aperture 212 and the bottom face of wheel bracket 72, but smaller than the perpendicular distance between the center of lower aperture 214 and the bottom face of wheel bracket 72. Sub-wheel 202 is also smaller than main wheel 90, while main wheel 90 is approximately the same size as rear wheel 44. These wheels sizes are suggestions and may be changed depending on loading, maneuverability and other concerns as would be understood by someone skilled in the art.

In operation, alternative unidirectional wheel assembly 200 functions as follows. When main wheel 90 is rotated clockwise as shown in FIG. 10 to cause movement in the forward direction as indicated by the arrow, sub-wheel 202 rotates counter-clockwise and secondary axle 204 slides to the lower aperture 214 due to friction between main wheel 90 and sub-wheel 202. In the lower aperture 214, there is a sub-wheel clearance 216 between the uppermost portion of sub-wheel 202 and the bottom face of wheel bracket 72. Thus, sub-wheel 202 rotates freely in the counter-clockwise direction based on the motion of main wheel 90 because of the frictional contact there between. Accordingly, main wheel 90 is free to rotate in the clockwise direction and allows forward movement of main wheel 90. When main wheel 90 is rotated in the counter-clockwise direction, sub-wheel 202 rotates clockwise and secondary axle 204 slides to the upper aperture 212 due to friction between main wheel 90 and sub-wheel 202. In the upper aperture 212, there is no sub-wheel clearance 216. Thus, sub-wheel 202 is frictionally held between the bottom face of wheel bracket 72 and the main wheel 90. Consequently, sub-wheel 202 cannot rotate further in the clockwise direction. Thus, main wheel 90 is prevented from rotating and no rearward movement of main wheel 90 is permitted. When main wheel 90 is rotated clockwise again, sub-wheel 202 disengages from the bottom of wheel bracket 72 and secondary axle 204 slides to lower aperture 214 allowing for forward motion once again.

In another embodiment of the scaffold 12, an alternative support mechanism 330 is utilized. As shown in FIG. 12, alternative support mechanism 330 includes a support bar 332 housed within vertical support member 20. The bottom of support bar 332 is connected to foot 334, while the top of support bar is connected to a brake lever 336. Brake lever 336 is connected to the top of support bar 332 at a proximal end 336 a and is free at a distal end 336 b. A pivot point 338 connects brake lever 336 to scaffold 12. Pivot point 338 is proximally located on brake lever 336, but distal from the connection to support bar 332, such that a force applied to distal end 336 b is substantially amplified and reapplied in the opposite direction to support bar 332. A latching system 340 is also provided to retain brake lever 336 when alternative support mechanism 330 is in an inactive state. At the lower end of support bars 332, feet 334 have a flange 342 for receiving one end of a spring 344. The other end of spring 344 is rigidly attached to a support plate 346 within vertical support member 20. Spring 344 is arranged such that it is substantially compressed between flange 342 and support plate 346 when foot 334 is in contact with the ground. Support bar 332 passes through an aperture 348 within support plate 346 so it can move freely in relation to support plate 346. Aperture 348 should be sized slightly larger than support rod 332 but considerably smaller than spring 344.

In function, alternative support mechanism 330 operates between an active and inactive state by actuating brake levers 336. When brake levers 336 are un-latched, springs 344 push down on feet 334, extending support bars 332 such that feet 334 contact the ground and lift unidirectional wheels 55 off the ground, characterizing the active state of alternative support mechanism 330. In this case, most of the front structure is supported by springs 344. When the distal end 336 b of brake lever 336 is depressed, the support bar 332 and foot 334 are pulled upward. Since brake lever 336 amplifies the force applied on its distal end 336 b such that a higher force is applied oppositely on the proximal end 336 a, spring 344 can be further compressed between flange 342 and support plate 346. At the point where foot 334 is completely off the ground, brake lever 336 engages latching system 340 and is held in place until disengagement of the latching system. Thus, the alternative support mechanism 330 is inactive and the wheeled structure can be moved accordingly.

Also shown in FIG. 12 is a modular movement apparatus 14 for use with a modular scaffold according to another embodiment of the present invention. The modular elements include a modular shaft 350, which is contained within and supported by the modular scaffold section, a lower shaft 352 which is affixed to wheel frame 52 and an upper shaft 354 which is affixed to operating device 56. Modular shaft 350 is rotatably supported in the modular scaffold section by a bearing 361. Mating is provided by rectangular keyways on the shafts that permit a rigid torsional connection for transmitting torque between the operating device 56 and wheel frame 52. In FIG. 12, upper shaft 354 has a male keyway 360 received within female keyway 362 of modular shaft 350. Similarly, modular shaft 350 has a male keyway 364 received within female keyway of lower shaft 352. Additional modular shafts 350 can be provided as connectors to be inserted between modular scaffold sections to provide a connector between modular shafts to transmit movement from an upper shaft 354 to a lower shaft 352. This design allows multiple modular scaffold sections to be placed upon each other to facilitate many different sized scaffold structures while maintaining the maneuverability of such a structure using the movement apparatus as previously described. Similar modularity of the support rods 132 and 332 could be achieved by using similar methods. It is also conceivable that telescopic rods could permit modularity of the braking or support structure.

An additional embodiment of the present invention is illustrated in FIG. 13 wherein an inclined main shaft 450 is implemented. Main shaft 450 is coupled to a lower shaft 452 and an upper shaft 454 by universal joints 456 and 458 respectively. Lower shaft 452 is also connected to wheel frame 52 and upper shaft 454 is connected to operating device 56. The configuration allows the operating device 56 to be more centrally located on scaffold 12 or any other desirable location. Having the operating device 56 centrally located permits a user to switch orientation when navigating in the forward and reverse directions. For example, while traveling in the forward direction a user would be located on one side of the operating device 56 to view obstacles in the forward path and when traveling in the reverse direction the user would move to the opposite side of operating device 56 to view obstacles in the rearward path.

In a further embodiment featured in FIG. 14 and FIG. 15, an inclined main shaft 450 is connected to a horizontal upper shaft 464 by a universal joint 468. Further, a vertically actuated operating device 470 is provided that allows a user to apply their full weight to actuate movement apparatus 14 using their feet. It is noted that although several torque transmission methods have been described for connecting operating device 56 to wheel frame 52, other transmission systems could be utilized including gears, chains, belts and other elements known in the art.

With a scaffold 12 according to the present invention, an operator can easily and efficiently move the scaffold 12 around a work site while remaining on the scaffold platform 34. This reduces the amount of work necessary to complete a job. Further, because the apparatus according to the invention has a relatively simple arrangement and few complex parts, it is easy and inexpensive to manufacture and incorporate into a variety of structures.

A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

The invention has been described with regard to a number of embodiments. However, it will be understood by persons skilled in the art that other variants and modifications may be made without departing from the scope of the invention as defined in the claims appended hereto. 

1. An apparatus for human-powered movement of a scaffold structure comprising: a) an operating device; b) a wheel frame; c) a transmission system connected between said operating device and said wheel frame and connectable to the scaffold structure, such that actuation of said operating device causes a corresponding movement in said wheel frame; and d) two unidirectional wheel assemblies provided at opposite ends of said wheel frame, said unidirectional wheel assemblies comprising: i) a wheel bracket connected to said wheel frame; ii) a unidirectional wheel supported in said wheel bracket.
 2. The apparatus of claim 1, wherein said unidirectional wheel comprises: a) a bi-directional main wheel; and b) a sub-wheel arranged in said wheel bracket adjacent to said bi-directional main wheel and adjacent to said wheel bracket, c) such that movement of said bi-directional main wheel in a first direction causes said sub-wheel to come into contact with said wheel bracket and prevents further rotation of said bi-directional main wheel in the first direction while movement of said bi-directional main wheel in a second direction causes said sub-wheel to move out of contact with said wheel bracket allowing further movement of said bi-directional main wheel in the second direction.
 3. The apparatus of claim 1, wherein said unidirectional wheel comprises: a) a bi-directional main wheel; and b) a block connected to said wheel bracket and arranged adjacent to said bi-directional main wheel, c) such that movement of said bi-directional main wheel in a first direction causes said block to abut against said bi-directional main wheel and said wheel bracket preventing further rotation of said bi-directional main wheel in the first direction while movement of said bi-directional main wheel in a second direction causes said block to disengage from said bi-directional main wheel or said wheel bracket allowing further movement of said bi-directional main wheel in the second direction.
 4. The apparatus of claim 1, wherein the apparatus further comprises a support mechanism such that activating said support mechanism causes the scaffold structure to be unsupported by said unidirectional wheel assemblies and deactivating said support mechanism causes the scaffold structure to be at least partially supported by said unidirectional wheel assemblies.
 5. The apparatus of claim 4, wherein said support mechanism substantially lifts said unidirectional wheels off the ground.
 6. The apparatus of claim 1, wherein the apparatus further comprises a support mechanism, said support mechanism comprising: a) a support bar; b) a biasing device connected to the scaffold structure for biasing said support bar to a first position; c) a latching mechanism connected to said support bar wherein said latching mechanism may be latched to the scaffold structure for retaining said support bar in a second position counter to said first position.
 7. The apparatus of claim 6, wherein said first position is defined such that said unidirectional wheel assemblies at least partially support the scaffold structure and wherein said second position is defined such that said unidirectional wheel assemblies do not support the scaffold structure.
 8. The apparatus of claim 6, wherein said second position is defined such that said unidirectional wheel assemblies at least partially support the scaffold structure and wherein said first position is defined such that said unidirectional wheel assemblies do not support the scaffold structure.
 9. The apparatus of claim 1, wherein said operating device is arranged to be operated by an operator's hands and arms.
 10. The apparatus of claim 1, wherein said operating device is arranged to be operated by an operator's feet and legs.
 11. The apparatus of claim 1, wherein said transmission system is a shaft.
 12. The apparatus of claim 11, wherein said shaft is modular for use with modular scaffold structures.
 13. The apparatus of claim 11, wherein the scaffold structure comprises a hollow vertical support and said shaft extends through said hollow vertical support.
 14. The apparatus of claim 11, wherein the scaffold structure comprises a journaling device for supporting said shaft.
 15. The apparatus of claim 1, wherein said transmission system comprises: a) a substantially inclined main shaft; b) a substantially vertical lower shaft connected between said wheel frame and said main shaft; and c) an upper shaft connected between said main shaft and said operating device.
 16. The apparatus of claim 15, wherein said upper shaft is located proximal to the central vertical axis of the scaffold structure.
 17. An apparatus for human-powered movement of a scaffold structure comprising: a) a horizontal lever bar; b) a horizontal wheel frame; c) a shaft connected between the center of said lever bar and the center of said wheel frame and connectable to the scaffold structure such that the scaffold structure is supported by said apparatus, such that actuation of said lever bar causes a corresponding movement in said wheel frame; and d) two unidirectional wheel assemblies provided at opposite ends of said wheel frame, said unidirectional wheel assemblies comprising: i) a wheel bracket connected to said wheel frame; ii) a unidirectional wheel supported in said wheel bracket, e) wherein actuating said lever bar in a first direction causes said wheel frame to pivot in a first angular direction about a first unidirectional wheel assembly attached to a first end of said wheel frame; and f) actuating said lever bar in a second direction causing said wheel frame to pivot in a second angular direction about a second unidirectional wheel assembly attached to a second end of said wheel frame opposite to said first end, resulting in movement of the scaffold structure.
 18. A method for human powered movement of a scaffold structure comprising: a) providing a movement apparatus to the scaffold structure, the movement apparatus comprising: b) an operating device; c) a wheel frame; d) a transmission system connected between said operating device and said wheel frame and connectable to the scaffold structure, such that actuation of said operating device causes a corresponding movement in said wheel frame; and e) two unidirectional wheel assemblies provided at opposite ends of said wheel frame, said unidirectional wheel assemblies comprising: f) a wheel bracket connected to said wheel frame; g) a unidirectional wheel supported in said wheel bracket; h) actuating said operating device in a first direction causing said wheel frame to pivot in a first angular direction about a first unidirectional wheel assembly attached to a first end of said wheel frame; and i) actuating said operating device in a second direction causing said wheel frame to pivot in a second angular direction about a second unidirectional wheel assembly attached to a second end of said wheel frame opposite to said first end, j) wherein pivoting said wheel frame in said first angular direction and then pivoting said wheel frame in said second angular direction results in movement of the scaffold structure.
 19. The method of claim 18, wherein an operator actuates said operating device using the operator's arms and hands.
 20. The method of claim 18, wherein an operator actuates said operating device using the operator's legs and feet. 